/**
 * 
 */
package com.example.sjt.util;

import java.util.Date;
import java.util.HashMap;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

/**
 * @author yuqy
 *
 */
public class JwtTokenUtils {

	public static final String TOKEN_HEADER = "Authorization";
	public static final String TOKEN_PREFIX = "Bearer ";

	private static final String SECRET = "xxxxxxxx";
	private static final String ISS = "xxxxxx";

	// 角色的key
	private static final String ROLE_CLAIMS = "rol";

	// 过期时间是3600秒，既是1个小时
	private static final long EXPIRATION = 3600L;

	// 选择了记住我之后的过期时间为7天
	private static final long EXPIRATION_REMEMBER = 604800L;

	// 创建token
	public static String createToken(String username, String role, boolean isRememberMe) {
		long expiration = isRememberMe ? EXPIRATION_REMEMBER : EXPIRATION;
		HashMap<String, Object> map = new HashMap<>();
		map.put(ROLE_CLAIMS, role);
		return Jwts.builder().signWith(SignatureAlgorithm.HS512, SECRET).setClaims(map).setIssuer(ISS).setSubject(username).setIssuedAt(new Date())
				.setExpiration(new Date(System.currentTimeMillis() + expiration * 1000)).compact();
	}

	// 从token中获取用户名
	public static String getUsername(String token) {
		return getTokenBody(token).getSubject();
	}

	// 获取用户角色
	public static String getUserRole(String token) {
		return (String) getTokenBody(token).get(ROLE_CLAIMS);
	}

	// 是否已过期
	public static boolean isExpiration(String token) {
		return getTokenBody(token).getExpiration().before(new Date());
	}

	private static Claims getTokenBody(String token) {
		return Jwts.parser().setSigningKey(SECRET).parseClaimsJws(token).getBody();
	}
}
